Insulating compound.



L. E. BARRINGER.

INSULATING COMPOUND.

APPLICATION FILED AUG. 7, 1907.

1,085,102. Patented a 27, 1914.

L/hseee' 0/7 Lawrence E. Barringer m 5M Q4;

Hisfittorneg.

UNITED STATES "PATENT OFFICE.

LAWRENCE EnBARR-INGER, OF SCHENECTADY, NEW YORKpASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPl R-ATION OF NEW YORK.

INSULATING COMPOUND.

Patented Jan. 27,1 914.

, 1907. Serial No. 387,548.

To all whom it may concern:

Be it known that I, LAWRENCE E. BAR- RINGER, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Insulating Compounds, of which the following is a specification.

This invention relates to electrical insulating materials and has for its object the provision of a compound, which in addition to having high insulating propertles, 1s

' hard, dense and impervious to moisture.

In carrying out my invention I combine .materials which, when properly treated,

form a hard material, the pores of which are filled with an impervious compound.

The accompanying drawing illustrates diagrammatically the various steps in the process of forming my new composition. I have found that what is known as artificial rubber or sulfurized oil is very desirable as a moisture-excluding filler, the reactions between the sulfur and oil being accompanied by a swelling or puiiing-up of the mass, to form a spongy, rubber-like product. Now by causing this reaction to occur in the pores of a compound throughout its structure, the latter is rendered waterproof, or impervious. The compound must be sufficiently strong to withstand the swelling action of the sulfurized oil.

I have found that by the proper combination of materials, the compound may be formed and the waterproof effect accomplished in the same operation. This is done by using materials which will saponify the same oil used for producing the sulfurized oil, as calcium hydrate or zinc oxid or the like. If these materials alone are moistened with oil and heated to the neighborhood of 200 C. a. solid mass is formed, quite strong and hard, but porous and easily disintegrated by water, although apparently insoluble. Now, if sulfur is added to the mixture, there being suflicient oil to react with both the sulfur and the lime or zinc oxid or other base, a hard, dense mass is formedimpervious and not attacked by water. Further, any mineral powder or inert material moistened with oil, such as linseed oil, and baked, becomes a solid, firm mass, quite strong and tough. This may be through the oxidization or other changes in the oil itself, caused by the heating, the

oxidized oil acting as a binder for the mineral particles. With the use of proper ingredients, therefore, three different reactions may occur in the same mass, viz., the formation of sulfurized'oil or artificial rubber, the formation of saponified oil, and the change to oxidized oil. The mass becomes suificiently hard before the formation of the sulfurized oil (which occurs at a temperature of from-150 to 280 C.) towithstand the pore-filling reaction, or the swelling due to the formation of the sulfurized oil.

In addition to the ingredients necessary for the reactions mentioned, an inert filling material may be used, as flint, ground slate, feldspar, or ground mica, or any mineral or rock powder which has good insulating qualities and is fairly refractory. Also a fibrous strengthening material, as asbestos, may be used to increase the strength and toughness, and also facilitate manufacture through making the materials hang together better when freshly molded.- Further, a coloring matter, as manganese dioxid, may be added to change the brownish color, which the composition would ordinarily have, to black.

A composition I found quite satisfactory is as follows:

Zinc oxid 20 Sulfur 8 Ground flint 40 Powdered talc 12 Short white asbestos 20 To these materials there is added, by weight, from 15 to 20 parts of boiled linseed oil and the whole is mixed in any suitable mixer until the mass is uniformly mixed throughout. The composition will then be found of a suitable consistency for pressing, which may be accomplished in steel molds in hydraulic presses, or may be molded by screw presses or in any other known manner. After molding to the desired shape' the pieces are subjected to a temperature of 150 to 220 C. for from 4 to 8 hours, depending upon the size of the pieces, which treatment produces the reactions above described and forms a dense, hard, impervious product, of good insulating qualities and mechanical strength. The compound, when out with a knife, somewhat resembles fiber in color and texture and also in that it may be machined without difficulty. But, unlike fiber, it is not inflammable andwill with stand considerable heat and will not warp or get out of shape after once beingformed and hardened.

The composition above given, of course, may be modified within a considerable range, both in the proportions of the ingredients and in the materials used to accomplish the same results. For instance, slaked lime may be used instead of the zinc oxid, or raw linseed oil may be used instead of the boiled linseed oil, or other oils may be used, as cotton seed oil or castor oil, but the linseed oil is preferable on account of its swelling or pufling up to a greater extent than the other oils mentioned. Or, the compound may be made either with. or without asbestos or other fibrous material. Or slate or feldspar or similar material may be used, instead of the flint. The mass may be .colored by manganese dioxid or by bone-black. If an organic coloring matter is used, as bone black, less is required and it is also necessary to use less in order not to seriously injure the insulating properties of the compound. As high as per cent. manganese dioxid may be used, replacing the flint or other inert matter, while almost the same color may be secured by using only 5 per cent. of bone-black.

While 200 to 220 .has been found the most suitable temperature a fairly hard product may be obtained as low as 150 and a hard, strong product is still obtained on carrying the temperature as high at 280 C. But in the case of the lower temperatures the hardening seems due mostly to the baking of the oil alone and the resulting product is not as water-resistant and permanent. The reactions of saponification and vulcanization of the oil require for best development in the neighborhood of 200 to 220 C. This gives a product which may be soaked in water for weeks without any apparent deterioration. The-temperatures above 220 do not give improvement in the qualities of the compound noticeable enough to warrant the use of the increased temperature; It will be further understood, of course, that the materials and proportions thereof above enumerated are given merely for purposes of illustration and hence may be varied without departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

'What I claim as new and desire to secure by Letters Patent of the United States, is,

'1. The process of forming a hard, dense insulating composition consisting of mixing oil and sulfur with a saponifying material and heating to a temperature which causes bolth saponification and sulfurization of the o1 2. The process of forming a hard, machinable insulating composition consisting of mixing oil and sulfur with a saponifying material and heating to a temperature of about 150200 C. to cause saponification and sulfurization to take place successively. ,f-"3-.--.The process of making a hard, impervious "composition which consists in mixing latter ingredient being in sufiicient amount to combine both with the saponifying material to make a hard, strong mass, and with sulfurized oil, molding the mixture and heating to a temperature at which the in gredients react.

able, dense composition which consists in mixing zinc oxid, sulfur and a substantial proportion of oil to combine with both the zinc oxid to make a hard, strong mass, and the sulfur to fill the pores of said mass with sulfurized oil, molding the mixture and heating the same to the reactiontemperature.

5. The process of making a hard, machinable composition impervious to moisture which consists in mixing substantially 20 parts of zinc oxid with sulfur 'and 15 to 20 parts of linseed oil, molding the mixture and heating to a temperature at which the oil and oxid react to form a hard porous mass and the sulfur will combine with some of the oil to fill the pores of said mass.

6. A hard dense insulating composition comprising sulfurized oil and saponified oil.

7. A dense, machinable insulating compound comprising a hardened mixture of linseed oil and a refractory material having its pores filled with sulfurized oil.

8. A hard dense insulating material which is impervious to moisture comprising a hard compound of an oil and a saponifying material and sulfurized oil filling the pores of said material.

9. A composition of matter comprising a strong, hard material of insulating properties and sulfurized oil filling the pores of said material.

10. A composition of matter comprising a strong, hard material consisting of inert material saponified oil, oxidized oil, and sulfurized oil filling the pores of said material.

In witness whereof, I have hereunto set my hand this 3rd day of August, 1907.

LAWRENCE. E. BARRINGER.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD.

the sulfur to fill the pores of said mass with- 4. The process of making a hard, machin-i .a saponifyin'g material, sulfur and oil, the 

